Help me get rid of the bog! 72 cb750

Posted by Bugteeth on May 20, 2013; 2:34pm
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Help-me-get-rid-of-the-bog-72-cb750-tp4040988.html

First off, i tried to look through as many of the posts as possible before posting but didn't see anything that i was confident was the problem. So sorry if someone asked this already.

I bought a 72 CB750 this winter that seemingly ran almost perfect. So now that spring is here and i've had it out a few times, i noticed that once it's completely warmed up (15 min or so) is starts to bog off the line. When i give it the first throttle twist it almost dies, usually doesn't but close. Once i am going through the gears it does fine.

So it does have some black smoke when you give it a good rev. I changed the plugs and after checking them after a short ride they were definitely on the black side. I barely have to choke it at all when starting so i would assume its getting too much gas. Which would make sense why it runs awesome until its fully warmed up. It already had a 4 into 1 when i bought it. Most everything else is stock, including the air box. I never really got to speak to the owner (odd story) before purchasing so i didn't get to ask about much about the bike. I dropped the rear shocks from 14" to 12.5". Could that effect anything since the bike sits so much lower?

I'm not a mechanic by any means and a lot of this stuff is all new to me. From chatting with random people i get the impression that its jetting related. Wanted to get some good advice first before taking anything apart.


Anyone have this issue before or have any suggestions? I would appreciate any help.